Not exactly. OmniStar XP, OmniStar HP, and RTX all use a satellite to get the correction data from the base stations to your rover. This eliminates the need for any radio or modem on the machine as the system can use the same antenna for both the GNSS satellites and the correction data.

RTX is available in either a slow convergence (requires only the OmniStar unlock on your rover) or a fast convergence (requires the RTK unlock on your rover). The fast convergence is only available in certain regions, a map is available on the RTX website.